An evaporator is provided in a refrigerator for absorbing heat to decrease the temperature in the refrigerator. A fan is also provided in vicinity of the evaporator to circulate the air inside the refrigerator through the evaporator. In this way, the temperature in the refrigerator is more uniform. In use, humid air may enter the refrigerator when the door is open. Water may then condensate on the evaporator and form ice. As more and more ice is formed on the evaporator, there is a possibility that the ice will reach the fan causing the load on the motor of the fan to increase gradually, resulting in a rising load current of the motor and thus causing the motor and the drive circuit thereof to be over-heated and thus come damaged. In this case, the temperature of a region for storing food in the refrigerator would rise because the air is not being circulated through the evaporator.
In the conventional technology, the above issue may be addressed by connecting a safety fuse in series with the motor. When the above issue occurs, the fuse will blow to turn off the motor. However, it is troublesome to replace the fuse for subsequent use. In the conventional technology, the above issue may also be addressed by providing an electronic control device and a temperature sensor. The electronic control device determines that the fan is blocked by ice when the temperature sensed by the temperature sensor is above a certain value, and then turns off the motor. However, it may take the sensor much time to sense the change in temperature in the case that the fan blocked by ice can still operate at a relatively low speed, during which the heat generated by the motor and the electronic components is more than that in normal situations because the fan is blocked from rotating, which may result in the motor and the drive circuit thereof to be damaged.